1. Field of the Invention
The present invention relates to a composition of a metal-incorporated VSB-5 molecular sieve with nanopores and its preparation method, in particular, to a composition of a metal-incorporated VSB-5 molecular sieve with a framework of VSB-5 molecular sieve comprising nickel, phosphorous, oxygen and metal, which is useful in various fields such as a hydrogen storage material, an optical and electric/electronic material, a sensor, a catalyst, a catalyst supporter and an adsorbent, and its preparation method performed in such a manner that a specific metal component is added in a predetermined mole ratio to a reaction mixture comprised of nickel and phosphorous compounds and the resultant mixture is crystallized in the presence of inorganic or organic base as a pH modifier to yield metal-incorporated VSB-5 molecular sieves in an economical and efficient manner.
2. Description of the Related Art
A nanoporous material of nickel and phosphorous, the so-called VSB-5 molecular sieve with pore openings composed of 24-membered ring of oxygen atoms has pores of about 6.4 Å, exhibits a catalytic activity for selective hydrogenation and dehydrogenation, and shows relatively higher thermal stability. Therefore, the VSB-5 molecular sieve has been highlighted as a porous solid inorganic material as compared to conventional zeolitic molecular sieves.
However, the procedure for synthesizing VSB-5 molecular sieve containing metal has not reported yet. Furthermore, the procedure for synthesizing VSB-5 molecular sieve not containing metal has not been well known. The only process reported so far for producing VSB-5 molecular sieve comprises the utilization of the diamine bases from 1,2-ethylene diamine to 1,8-octane diamine and nickel and phosphorous compounds (J. Am. Chem. Soc., 125:1309-1312(2003); and Angew. Chem. Int. Ed., 40:2831-2834(2001)). As the diamine base, 1,3-diaminopropane (DAP) is mainly used. The composition of VSB-5 molecular sieve includes as mole ratio of about 1.0 Ni: 2.1 P: 5.0 DAP: 140 H2O, which undergoes a hydrothermal reaction for 5-6 days at 180° C. to yield VSB-5 molecular sieve. However, the diamines used as a base are generally expensive and require heat treatment for its removal after the synthesis of the VSB-5 molecular sieve. Furthermore, the heat treatment results in the destruction or occlusion of pore structures of the VSB-5 molecular sieve, which highly decreases the surface area of the VSB-5 molecular sieve thus reducing efficiency of its applications.
Meanwhile, the molecular sieve of metal aluminophosphate prepared by incorporating metal into the molecular sieve of aluminophosphate has been applied to various catalytic reactions and the properties of its metal have been very likely to be utilized (Chemical review, 99:635-663(1999). In this regard, it could be recognized that the metal-incorporated VSB-5 molecular sieve shows improved applicability and usefulness. However, there has been no publication on the metal-incorporated VSB-5 molecular sieve.
Therefore, there remains a need in the art for developing a VSB-5 molecular sieve containing metal and a novel method for preparing a VSB-5 molecular sieve containing metal in an economical manner.